Electromagnetic switch arrangement



Dec. 18, 1956 KESSELRING 2,774,920

ELECTROMAGNETIC SWITCH A RANGEMENT Filed Oct. 4, 1951 2 Sheets-Sheet 1Fig.2

' I-NVENTOR'.

FRITZ KESSELRINQ AT T'Y Dec. 18, 1956 F. KESSELRING 2,774,920

ELECTROMAGNETIC SWITCH ARRANGEMENT Filed Oct. 4, 1951 2 SheetsSheet 2 AINVENTOR:

FRITZ KESSELRING United States Patent ELECTROMAGNETIC SWITCH ARRANGEMENTFritz Kesselring, Zollikon-Zurich, Switzerland, assignor to FKG FritzKesselring Geratebau, Bachtobci-Weinfelden, Switzerland, a Swisscorporation Application October 4, 1951, Serial No. 249,731

r 9 Claims. (Cl. 317-156) My present invention relates to anelectromagnetic switch arrangement with at least one electromagneticallyactuated switching element actuation of which in closed position causestwo stationary contacts to be connected and to complete the electriccircuit to be switched, and two magnetic systems of which one serves forclosing the said switching element, the second serving for opening saidelement, characterized by the fact that the switching element arrangedbetween the pole pieces of the two magnetic systems is influenced, apartfrom the force of gravity, by magnetic forces only.

The accompanying drawings disclose three embodiments of this invention,Figs. 1 and 2 showing a switch arrangement in a transformer circuit,Figs. 3 and 4 showing a switch cartridge according to the invention.

Referring to Fig. 1, the numeral 61 designates the alternating currentsource, 62 a saturable reactor with an air gap '63, 64 is the mainwinding tapped at 65 and 66. The numeral 67 designates an auxiliarycoil, 68 and 69 are valves, more particularly dry rectifiers. 70 is anadjustable shunt resistance, 71 a condenser. The magnetic closing systemof the switch arrangement is generally indicated at 72, and it comprisesthe poles 73 and 74.

The said magnetic closing system comprises the main winding 75 and theauxiliary closing coil '76. i The magnetic opening system is designatedby the reference nu-' meral 79 and comprises the poles 80 and 81, an airgap 86 bridged by the permanent magnet 82, and the opening coil 83. Inparallel relation to the point of interruption is arranged the valve 84,and 8'5 designates the load. Between the pole pieces of the two magneticsystems is arranged the switching element (armature) 78. It is evidentthat several such switching elements may be arranged serially. The polefaces of the poles 73, 74, 80 and 81 enclose spaces of squarecross-section open at the corners, in which the armature or armaturesare arrange In addition, the poles 73 and 74 of the magnetic closingsystem 72 also constitute the stationary contacts.

This arrangement operates in the following manner: When a current beginsto How in the winding 64, a voltage pulse occurs between the taps 65 and66 causing an impulse through the windings 75 and 76 and the Valve means68. Simultaneously, the condenser 71 is charged. The effect of thisimpulse attracts the armature 78 thereby bridging the poles 73 and 74.At the end of the voltage pulse, the condenser 71 discharges through thewindings 75, 76 so that magnetization is extended beyond the duration ofsaid pulse until the energiza-tion of the main winding 75 ensuressufficient holding power. When the main current approaches its zerovalue, the magnetization of the reactor 62 is again reversed. Thevoltage between the taps 65 and 66 is of opposite polarity. No currentcan flow through the closing windings 75, 76 by reason of the blockingwinding of valve 68. However, a voltage pulse is created in the winding67 and now energizes the opening coil 83 in such a manner that thelatter assists the magnetizing effect of the permanent magnet 82. Thiscauses the armature 7 8 to be attracted in the opening sense likecurrent valve 43, e. g'. a dry rectifier.

Patented Dec. 18, 1956 clear of the poles 73 and 74. Owing to the effectof the permanent magnet 82, the armature 78 then remains in openposition. When magnetization of the reactor 62 is reversed for closing,the cycle of the closing circuit described is repeated. In addition,however, a current flows from the winding 67 through the resistance 70and the opening coil 83, in opposite direction, causing the attractiveforce of the permanent magnet 82 to be decreased to such a value thatthe armature 78 would drop even without the attraction of the magneticsystem 72. It will be seen that the acceleration of the armature in theclosing and opening directions only occurs by means of magnetic forcesgenerated on the one hand by the energization of the closing winding 76,and, on the other hand, by the energization of the opening winding 83.The permanent magnet 82 only secures the open position of the switch incurrentless condition. Its effect is compensated by counter-energizationof the winding 83 in the closing process.

Fig. 2 shows an embodiment of the present invention specially employedfor high current values. The numeral designates the alternating currentsource, 91 the saturable reactor with windings 92 and 93, and thepreenergization system 94. The main energization of the saturablereactor 91 occurs through the currentcarrying conductor 95, i. e. thereactor 91 is designed as a singlewire transformer. 96, 97 designatevalves, 98, 99 resistances.

The magnetic closing system 100 comprises the poles 101 and 102 and anair gap 115. A permanent magnet 103 bridges the gap 115. The ma neticclosing system is provided with an auxiliary closing coil 104. Mainenergization is effected by means of the current passage through thebars 105 and 106 which also serve as stationary contacts arranged belowthe gap 117 between the pole faces 101 and 102 of the magnetic closingsystem 100 and connected by the armature or armatures 107 in closedcondition. The bars 105, 106 are insulated and adjacent, and represent astructure resembling a singlewire transformer in conjunction with themagnetic system 100. The magnetic opening system is designated by 116,its poles by 108 and 109. It also comprises an air gap 114 and apermanent magnet 110 bridging said gap, in addition also the openingcoil 111. The valve bridging the stationary contacts 105, 106, isdesignated by the reference numeral 112, 113 being the load. Between thepole pieces of the two magnetic systems 100 and 116, the armature 107 isarranged as a circuit element, several such elements in serialarrangement being possible. The pole faces of the two magnetic systems100 and 116 again define spaces of generally square cross section withopen corners.

The operation of this arrangement corresponds in all essentials to theoperation of the arrangement disclosed in Fig. 1. The arrangement of thepermanent magnet 103 provides for the armature 107 to be held in closedposition until the zero value is approached. On opening, the efiect ofthe magnet 103 is compensated by the return current of the valve 96flowing through the resistance 98, the operation being similar to thatdescribed for the closing magnet according to Fig. 1. In closed positionthe armature or armatures 107 cause the two bars 105, 106 to beconnected. The armature or armatures are thus influenced apart from theforce of gravity by magnetic forces only.

Fig. 3 shows a cross section and Fig. 4 a longitudinal section along theline AA in Fig. 3 of a single-wire cartridge, in which the gap 40 isarranged in parallel relation to the two current bars 41, 42 forming thestationary contacts. Between the bars is arranged a plate- The recesses44 and 45 serve to increase the insulation distances. The magneticclosing system comprises two systems 46 and 46a and encloses the bars 41and 42. The impulse winding 47 is connected only with the magneticsystem 46 in order to reduce its inductance. Furthermore, a magneticopening system 50 with the winding 51 is provided. The referencenumerals 4S and 48a designate disc-shaped armatures carrying theconducting current bridges 49 at their lower ends and serially arrangedin parallel relation between the pole pieces of the two magnetic systems46 and 46:; respectively. For the sake of clarity, the serially arrangedarmatures 48, 48a are not shown in Fig. 4. Finally, 52 designates thehousing, 53 being the base-plate through which the elbows 54 and 55 ofthe bars 41 and 42 project downwardly. In order to secure the armatures48 and 48a against dropping out, the closures 56a and 56b are provided.In these three embodiments the pole faces of the two magnetic systemsdefine spaces of generally square cross-section with open corners, inwhich the armatures are disposed.

The operation of the arrangement is as follows: As soon as a forwardcurrent begins to flow through the valve 43, the impulse winding isenergized and the effect of the opening winding 51 reduced, which causesthe armatures 48 of the magnetic impulse system to be attracted and thebars 41, 42 to be connected. The increasing main current graduallyincreases the energiza' tion of the main magnetic system 46a and thusthe associated armatures 48a are attracted. When the main current againapproaches its zero value, only the armatures 48 are strongly attractedby the magnetic field generated by the impulse winding, while thearmatures 48a only loosely rest on the bars 41 and 42. In theneighbourhood of the zero value, a counter-impulse is generated in amanner similar to that disclosed in Figs. 1 and 2, so that the currentin the winding 47 practically drops to zero While the current of theopening winding 51 is substantially increased. This causes all armatures48 and 43a to move into open position.

The advantage of the switch arrangement resides mainly in the fact thatmechanical supports for the switching element are dispensed with so thatno additional energy need be expended in order to counteract the effectof an opening spring when the arrangement is switched in, and that theomission of all supporting means simplifies the manufacture, assemblyand setting of the arrangement. The magnetic opening arrangementprovides the additional advantage that the switching elements aremagnetically held in their final positions, and that all backwardrocking, which would entail a reduction of dielectric strength, ispractically impossible.

What I claim is:

1. An electromagnetic switch arrangement for the control of current flowfrom an alternating current source to a load comprising an electricalcircuit closing magnetic system, an electrical circuit opening magneticsystem, a switching element, a saturable reactor, and an electronicdevice, said circuit closing magnetic system comprising a first andsecond pole piece electrically insulated from each other and having anair gap therebetween, said switching element electrically bridging saidair gap when said switching element is moved to circuit closed position,a main closing winding wound on at least one pole piece of said closingmagnetic system and electrically connected to one pole piece formagnetically energizing said closing magnetic system when said mainclosing winding is electrically energized, a main winding on saidsaturable reactor, an electrical circuit for connecting said electronicdevice to said pole pieces, an electrical circuit for connecting theload to the other of said pole pieces, said main winding and said mainclosing winding being electrically connected in series with saidalternating current source and load through said pole pieces andelectronic means, said switching element short circuiting saidelectronic means when moved to bridge said one air gap of said poles ofsaid closing magnetic system, a secondary winding on said saturablereactor, an opening winding on said opening magnetic system formagnetically energizing said opening magnetic system when said openingwinding is electrically energized, first means to prevent fullenergization of said opening winding when said main and auxiliaryclosing winding are energized during one-half of the alternating currentcycle to attract said switching element to closed position and secondmeans during the other half of the alternating current cycle to preventfull energization of said auxiliary and main closing windings when saidopening winding is fully energized from said secondary winding of saidsaturable reactor to move said switching element to open position.

2. An electromagnetic switch arrangement for the control of current flowfrom an alternating current source to a load comprising an electricalcircuit closing magnetic system, an electrical circuit opening magneticsystem, a switching element, a saturable reactor, and an electronicdevice, said circuit closing magnetic system comprising a first andsecond pole piece electrically insulated from each other and having anair gap therebetween, said switching element electrically bridging saidair gap when said switching element is moved to circuit closed position,a main closing winding wound on at least one pole piece of said closingmagnetic system and electrically connected to one pole piece formagnetically energizing said closing magnetic system when said mainclosing winding is electrically energized, a main winding on saidsaturable reactor, an electrical circuit for connecting said electronicdevice to said pole pieces, an electrical circuit for connecting theload to the other of said pole pieces, said main winding and said mainclosing winding being electrically connected in series with saidalternating current source and load through said pole pieces andelectronic means, said switching element short circuiting saidelectronic means when moved to bridge said one air gap of said poles ofsaid closing magnetic system, a secondary winding on said saturablereactor, an opening winding on said opening magnetic system formagnetically energizing said opening magnetic system when said openingwinding is electrically energized, first means to prevent fullenergization of said opening winding when said main and auxiliaryclosing winding are energized during one-half of the alternating currentcycle to attract said switching element to closed position and secondmeans during the other half of the alternating current cycle to preventfull energization of said auxiliary and main closing windings when saidopening winding is fully energized from said secondary winding of saidsaturable reactor to move said switching element to open position and athird means connected in said opening magnetic system, said third meansbeing effective to maintain said switching element in disengagedposition when said switch element is moved to disengaged position byenergization of said opening winding.

3. An electromagnetic switch arrangement for the control of current flowfrom an alternating current source to a load comprising an electricalcircuit closing magnetic system, an electrical circuit opening magneticsystem, a switching element, a saturable reactor, and an electronicdevice, said circuit closing magnetic system comprising a first andsecond pole piece electrically in sulated from each other and having anair gap therebetween, said switching element electrically bridging saidair gap when said switching element is moved to circuit closed position,a main closing winding wound on at least one pole piece of said closingmagnetic system and electrically connected to one pole piece formagnetically energizing said closing magnetic system when said mainclosing winding is electrically energized,- a main winding on saidsaturable reactor, an electrical circuit for connecting said electronicdevice to said pole pieces, an electrical circuit for connecting theload to the other of said pole pieces, said main winding and said mainclosing winding being electrically connected in series with saidalternating current source and load {through said pole pieces andelectronic means, said switching element short circuiting saidelectronic means when moved to bridge said one air gap of said poles ofsaid closing magnetic system, a secondary winding on said saturablereactor, an opening winding on said opening magnetic system formagnetically energizing said opening magnetic system when said openingwinding is electrically energized, first means to prevent fullenergization of said opening winding when said main and auxiliaryclosing winding are energized during one-half of the alternating currentcycle to attract said switching element to closed position and secondmeans during the other half of the alternating current cycle to preventfull energization of said auxiliary and main closing windings when saidopening winding is fully energized from said secondary winding ofsaid'saturable reactor to move said switching element to open positionand electronic means controlled from said source of alternating currentfor rendering said opening magnetic system ineffective during theenergization of said closing magnetic system.

4. An electromagnetic switch arrangement for the control of current flowfrom an alternating current source to a load comprising an electricalcircuit closing magnetic system, an electrical circuit opening magneticsysterm, a switching element, a saturable reactor, and an electronicdevice, said circuit closing magnetic system comprising a first andsecond pole piece electrically insulated from each other and having anair gap therebetween, said switching element electrically bridging saidair gap when said switching element is moved to circuit closed position,a main closing winding wound on at least one pole piece of said closingmagnetic system and electrically connected to one pole piece formagnetically energizing said closing magnetic system when said mainclosing winding is electrically energized, a main winding on saidsaturable reactor, an electrical circuit for connecting said electronicdevice to said pole pieces, an electrical circuit for connecting theload to the other of said pole pieces, said main winding and said mainclosing winding being electrically connected in series with saidalternating current source and load through said pole pieces andelectronic means, said switching element short circuiting saidelectronic means when moved to bridge said one air gap of said poles ofsaid closing magnetic system, a secondary winding on said saturablereactor, an opening winding on said opening magnetic system formagnetically energizing said opening magnetic system when said openingwinding is electrically energized, first means to prevent fullenergization of said opening winding when said main and auxiliaryclosing winding are energized during one-half of the alternating currentcycle to attract said switching element to closed position and secondmeans during the other half of the alternating current cycle to preventfull energization of said auxiliary and main closing windings when saidopening winding is fully energized from said secondary winding of saidsaturable reactor to move said switching element to open position, apermanent magnet for energizing said open magnetic system, saidpermanent magnet being eflective to maintain said switching element inopen position when said switching element is moved to open position bysaid opening winding and while said main closing winding isde-energized.

5. An electromagnetic switch arrangement for the control of current flowfrom an alternating current source to a load comprising an electricalcircuit closing magnetic system, an electrical circuit opening magneticsystem, a switching element, a saturable reactor, and an electronicdevice, said circuit closing magnetic system comprising a first andsecond pole piece electrically insulated from each other and having anair gap therebetween, said switching element electrically bridging saidair gap when said switching element is moved to circuit closed position,a main closing winding wound on at least one pole piece of said closingmagnetic system and electrically connected to one pole piece formagnetically energizing said closing magnetic system when said mainclosing winding is electrically energized, a main winding on saidsaturable reactor, an electrical cir cuit for connecting said electronicdevice to said pole pieces, an electrical circuit for connecting theload to the other of said pole pieces, said main winding and said mainclosing winding being electrically connected in series with saidalternating current source and load through said pole pieces andelectronic means, said switching element short circuiting saidelectronic means when moved to bridge said one air gap of said poles ofsaid closing magnetic system, a secondary winding on said saturablereactor, an opening winding on said opening magnetic system formagnetically energizing said opening magnetic system when said openingwinding is electrically energized, first means to prevent fullenergization of said opening winding when said main and auxiliaryclosing windings are energized during one-half of the alternatingcurrent cycle to attract said switching element to closed position andsecond means during the other half of the alternating current cycle toprevent full energization of said auxiliary and main closing windingswhen said opening winding is fully energized from said secondary windingof said saturable reactor to move said switching element to openposition, and additional means for controlling the magnetization of saidopening mag netic system to maintain said switching element in openposition when said switching element is moved to open position by saidopening winding and while said main closing winding is de-energized.

6. An electromagnetic switch arrangement for the control of current flowfrom an AC. source to a load comprising an electrical circuit closingmagnetic system, an electrical circuit opening magnetic system, aswitching element, a saturable reactor, a first and second stationarycontact and an electronic device; said circuit closing magnetic systemcomprising a first and second pole piece having an air gap therebetween,said switching element being movable into and out of bridgingrelationship with respect to sa1d air gap; said stationary contactsbeing positioned to be engaged by said switching element when saidswitching element is moved into bridging relationship with respect tosaid air gap; said saturable reactor comprising a main winding and afirst and second secondary winding; said A.-C. source, said saturablereactor main winding, said pair of stationary contacts, and said loadbeing connected in series; said saturable reactor first secondarywinding being connected to energize said electromagnetic switchoperating winding responsive to a predetermined condition ofunsaturation of said saturable reactor to thereby magnetically energizesaid closing magnetic system; an electrical circuit for connecting saidelectronic device across said stationary contacts, said switchingelement short circuiting said electronic means when moved to engage saidstationary contacts; an opening winding on said opening magnetic systemfor magnetically energizing said opening magnetic system when saidopening winding is electrically energized; said saturable reactor secondsecondary Winding being connected to energize said opening windingresponsive to a predetermined condition of unsaturation of saidsaturable reactor, a first means to prevent full energization of saidopening winding when said closing winding is energized to attract saidswitching element to a closed position and a second means to preventfull energization of said closing winding when said opening winding isenergized to move said switching element out of engagement with saidstationary contacts.

7. An electromagnetic switch arrangement for the control of current flowfrom an A.-C. source to a load comprising an electrical circuit closingmagnetic system, an electrical circuit opening magnetic system, aswitching element, a saturable reactor, a first and second stationarycontact and an electronic device; said circuit closing magnetic systemcomprising a first and second pole piece having an air gap therebetween,said switching element being movable into and out of bridgingrelationship with respect to said air gap; said stationary contactsbeing positioned to be engaged by said switching element when saidswitching element is moved into bridging relationship with respect tosaid air gap; said saturable reactor comprising a main winding and afirst and second secondary winding; said A -C. source, said saturablereactor main winding, said pair of stationary contacts, and said loadbeing connected in series; said saturable reactor first secondarywinding being connected to energize said electromagnetic switchoperating winding responsive to a predetermined condition ofunsaturation of said saturable reactor to thereby magnetically energizesaid closing magnetic system; an electrical circuit for connecting saidelectronic device across said stationary contacts, said switchingelement short circuiting said electronic means when moved to engage saidstationary contacts; an opening winding on said opening magnetic systemfor magnetically energizing said opening magnetic system when saidopening winding is electrically energized; said saturable reactor secondsecondary Winding being connected to energize said opening windingresponsive to a predetermined condition of unsaturation of said saturale reactor, a first means to prevent full energization of said openingwinding when said closing winding is energized to attract said switchingelement to a closed position and a second means to prevent fullenergization of said closing winding when said opening winding isenergized to move said switching element out of engagement with saidstationary contacts; said first and second stationary contactscomprising a first and second bar arranged below said first air gap.

8. An electromagnetic switch arrangement for the control of current flowfrom an A.-C. source to a load comprising an electrical circuit closingmagnetic system, an electrical circuit opening magnetic system, aswitching element, a saturable reactor, a first and second stationarycontact and an electronic device; said circuit closing magnetic systemcomprising a first and second pole piece having an air gap therebetween,said switching element being movable into and out of bridgingrelationship with respect to said air gap; said stationary contactsbeing positioned to be engaged by said switching element when saidswitching element is moved into bridging relationship with respect tosaid air gap; said saturable reactor compris'1g winding and a first andsecond secondary winding; said :L-C. source, said saturable reactor mainwinding, said pair of stationary contacts, and said load connected inseries; said saturable reactor first secondary winding being connectedto energize said electromagn tic switch operating winding responsive toa predetermined condition of unsaturation of said saturable reactor tothereby magnetically energize said closing magnetic system; anelectrical circuit for connecting said electronic device across saidstationary contacts, said switching element short circuiting saidelectronic means when moved to engage said stationary contacts; anopening winding said opening magnetic system for magneticaily ener- "igsaid opening magnetic system when said opening w nding is elecnicailyenergized; said saturable reactor second secondary winding beingconnected to energize said opening Winding responsive to a predeterminedcondition of unsaturation of said saturable reactor, a first means toprevent full energization of said opening winding when said closingwinding is energized to attract said switching element to a closedposition and a second means to prevent full energization of said closingwinding when said opening winding is energized to move said switchingelement out of engagement with said stationary contacts; said closingmagnetic structure comprising a second air gap therein; a permanentmagnet; said permanent magnet being positioned to bridge said second airgap.

9. An electromagnetic switch arrangement for the control of current flowfrom an A.-C. source to a load comprising an electrical circuit closingmagnetic system, an electrical circuit opening m netic system, aswitching element, a saturable reactor, a st and second stationarycontact and an electronic device; said circuit closing magnetic systemcomprising a first and second pole piece having an air gap therebetween,said switching element being movable into and out of bridgingrelationship with respect to said air gap; said stationary contactsbeing positioned to be en aged by said switching element when saidswitching element is moved into bridging relationship with respect tosaid air gap; said saturable reactor comprising a main winding and afirst and second secondary winding; said A.-C. source, said saturablereactor main winding, said pair of stationary contacts, and said loadbeing connected in series; said saturable reactor first secondarywinding being connected to energize said electromagnetic switchoperating winding responsive to a predetermined condition ofunsaturation of said saturable reactor to thereby magnetically energizesaid closing magnetic system; an electrical circuit for connecting saidelectronic device across said stationary contacts, said switchingelement short circuiting said electronic means when moved to engage saidstationary contacts; an opening winding on said opening magnetic systemfor magnetically energizing said opening magnetic system when saidopening winding is electrically energized; said saturable reactor secondsecondary winding being connected to energize said opening windingresponsive to a predetermined condition of unsaturation of saidsaturable reactor, a first means to prevent full energization of saidopening winding when said closing winding is energized to attract saidswitching element to a closed position and a second means to preventfull energization of said closing winding when said opening winding isenergized to move said switching element out of engagement with saidstationary contacts; said opening and closing magnetic structures havingan air gap therein for receiving a permanent magnet to therebymagnetically bias said magnetic structures.

References Cited in the file of this patent UNITED STATES PATENTS(Addition td No. 887,127)

